Hand-held power tools that use internal combustion as a power source are known. In particular, fastener driving tools are known that drive fasteners, such as nails, into a work piece or substrate. The tools ignite a fuel/air mixture in a combustion chamber to forcibly drive a piston, which then ejects the fastener from the tool. The effectiveness of the prior art tools is largely limited by their efficiency in rapidly igniting the complete volume of fuel/air mixture. If insufficient volumes of fuel ignite, the device delivers unsuitable driving forces to the fastener. If the tool produces unreliable power outputs, the fasteners may be driven to unsatisfactory depths or insufficiently seated. Prior art devices in the past have attempted to address these inefficiencies by making a larger tool and wasting larger volumes of fuel.
Particular examples of such prior art devices are described in International Patent Publication No. WO 2005/063449, the entire disclosure of which is hereby incorporated by cross-reference. In view of the deficiencies of the prior art, the present invention seeks to provide a hand held power tool, in general, and a fastener driving tool, in particular, that will ameliorate or overcome at least one of the deficiencies of the prior art or at least offer a useful alternative.